ABSTRACT: Alzheimer’s disease (AD) is a genetically complex and heterogeneous disorder. Although the clinical manifestations and the pathological features have been well elucidated, a clear etiology of AD is still unknown to this day. In the past few decades, investigations have elucidated that both the genetic and the environmental factors are capable of causing the development of AD. We report a patient with clinically diagnosed earlyonset Alzheimer's disease, age of onset 45 years. Genetic analysis revealed two MTHFR heterozygous polymorphisms C677T and A1298C.